This tool determine change in pump head vs flow curve when two similar pumps are operating in either series or parallel configuration.

**Pump Curve**

\displaystyle \displaystyle Head(Q) = A_{2}.Q^{2}+A_{1}.Q+A_{0}

where Q is pump flowrate and Head(Q) is a 2nd order polynomial function based on Q.

\displaystyle \displaystyle Head(Q) = A_{3}.Q^{3}+A_{2}.Q^{2}+A_{1}.Q+A_0

where Q is pump flowrate and Head(Q) is a 3rd order polynomial function based on Q.

**Pump System**

**Pump in Series**

In series arrangement, each pump handles same flow rate, but the total head produced by the combination of pumps will be additive. Since each pump generates a head H corresponding to a flow Q, when connected in series, the total head developed is Ht = H1 + H2, where H1, H2 are the heads developed by the pump in series at the common flow rate Q.

**Pump in Parallel**

With pumps in parallel, the flow rates are additive with a common head. The flowrate Qt is split between the inlet into Q1 and Q2. Each pump develops the same head H at the corresponding capacity. Thus, the first pump at capacity Q1 develops the same head H as the second pump at capacity Q2.

**Pump Head Vs Flow Curve**

**Pump System**